1. Field of the Invention
This invention relates to microprocessors. In particular, the invention relates to management.
2. Description of Related Art
Mobile platforms have historically been faced with power and thermal management challenges due to the small form factor, limited power source availability, and relatively high power processors. Techniques have been developed to reduce processor power dissipation.
One technique is to use throttling a stop clock (STPCLK#) signal to the processor. When STPCLK# signal is asserted to the processor, the processor enters a low power state such Mobile Quick Start or stop grant. When STPCLK# is de-asserted, the processor resumes execution. Throttling using STPCLK# involves modulating STPCLK# signal at a specific frequency and duty cycle, whereby effectively the processor operates at a reduced frequency. Throttling using STPCLK# has a number of drawbacks. First, it is complicated and requires complex external interface circuits and protocol. Second, it is not compatible with software standards in power management. Third, it is not efficient. Fourth, it is not flexible in generating an arbitrary duty cycle for the processor state.
Therefore, there is a need to have a technique for power management that can overcome the above drawbacks.